package cn.site.core.utils;


import java.io.IOException;

import org.apache.commons.lang3.Validate;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.annotation.Lazy;
import org.springframework.core.io.DefaultResourceLoader;
import org.springframework.stereotype.Service;

/**
 * 以静态变量保存Spring ApplicationContext，可在任何代码任何地方任何时候取出ApplicationContext
 *
 * @author Zaric
 */
@Service
@Lazy(false)
public class SpringContextHolder implements ApplicationContextAware, DisposableBean {

    private static ApplicationContext applicationContext = null;
    private static Logger logger = LoggerFactory.getLogger(SpringContextHolder.class);

    /**
     * 检查ApplicationContext不为空
     */
    private static void assertContextInjected() {
        Validate.validState(applicationContext != null, "applicationContxt属性未注入，请在applicationContext.xml中定义SpringContextHolder.");
    }

    /**
     * 取得存储在静态变量中的ApplicationContext
     */
    public static ApplicationContext getApplicationContext() {
        assertContextInjected();
        return applicationContext;
    }

    public static String getRootRealPath() {
        String rootRealPath = "";
        try {
            rootRealPath = getApplicationContext().getResource("").getFile().getAbsolutePath();
        } catch (IOException e) {
            logger.warn("获取系统根目录失败");
        }
        return rootRealPath;
    }

    public static String getResourceRootPath() {
        String rootRealPath = "";
        try {
            rootRealPath = new DefaultResourceLoader().getResource("").getFile().getAbsolutePath();
        } catch (IOException e) {
            logger.warn("获取资源根目录失败");
        }
        return rootRealPath;
    }

    /**
     * 从静态变量applicationContext中获取Bean，自动转为所赋值对象的类型
     */
    @SuppressWarnings("unchecked")
    public static <T> T getBean(String name) {
        assertContextInjected();
        return (T) applicationContext.getBean(name);
    }

    /**
     * 从静态变量applicationContext中获取Bean，自动转型为所赋值对象的类型
     */
    public static <T> T getBean(Class<T> requiredType) {
        assertContextInjected();
        return applicationContext.getBean(requiredType);
    }

    /**
     * 清除SpringContextHolder中的ApplicationContext为null
     */
    public static void clearHolder() {
        if (logger.isDebugEnabled()) {
            logger.debug("清除SpringContextHolder中的ApplicationContext对象：" + applicationContext);
        }
        applicationContext = null;
    }

    /**
     * 实现DisposableBean接口，在Context关闭时清理静态变量
     */
    @Override
    public void destroy() throws Exception {
        SpringContextHolder.clearHolder();
    }

    /**
     * 实现ApplicationContextAware接口，注入Context到静态变量中
     */
    @Override
    public void setApplicationContext(ApplicationContext applicationContext)
            throws BeansException {
        logger.debug("织入ApplicationContext到SpringContextHolder : {}", applicationContext);
        if (SpringContextHolder.applicationContext != null) {
            logger.info("SpringContextHolder中的ApplicationContext被覆盖，原有的ApplicationContext为：" + SpringContextHolder.applicationContext);
        }
        SpringContextHolder.applicationContext = applicationContext;
    }

}
